HI there

I need to record a basic voiceover for a screencast tutorial. I have a small all in one jack/mic which plugs into my laptop mic input but when I use this, a buzzing is audible which isn't when I use it for skype. I assume this is the laptops internal working.

My Q is therefore what is the best way to do this on a budget? In particular:

a) Will a mic with a longer lead sort out the buzzing and will any old skype microphone give an acceptable sound? As I say, quality really isn't important as long as the audio is legible and clear
b) any recommendations for mics?

I have a USB audio interface input box if it helps.
I don't want to spend too much!